Objective To investigate the value of MR T2* in evaluation of liver iron overload caused by long term blood transfusion.Methods Thirty one patients with long term blood transfusion were collected.Both serum ferritin(SF)and CRP levels were measured and the adjusted serum ferritin(ASF)concentration was calculated.MRI of the maximum cross-sectional liver was performed using a 1.5T scanner (Siemens Avanto).The T2* value of the liver was measured,and the correlation analysis was carried out.Twenty one normal volunteers served as controls.The transfusion group was divided into iron overload group and non overload group,and differences between groups were analyzed.Results The correlation coefficient in 31 patients between liver T2* value and SF,ASF and blood transfusion volume was-0.695,-0.728 and -0.657 respectively,and the difference was statistically significant(P<0.05).The correlation coefficient between SF and blood transfusion volume was 0.518,and the difference was statistically significant(P<0.05).There was difference in T 2* value between three groups.Conclusion MR T2* has some practical value in the evaluation of liver iron overload in patients with long term blood transfusion.

Objective:To assess the feasibility of delayed-enhancement MRI in contouring the lumpectomy cavity (LC) for patients with invisible seroma or a low cavity visualization score (CVS≤2) in the excision cavity after breast-conserving surgery (BCS).Methods:Twenty-six patients with stage T 1-2N 0M 0 who underwent prone radiotherapy after BCS were recruited. The LC delineated on CT simulation images was denoted as LC CT. The LCs delineated on T 2WI, as well as on different delayed phases (2-, 5-and 10-minute) of delayed-enhancement T 1WI were defined as LC T2, LC 2T1, LC 5T1 and LC 10T1, respectively. Subsequently, the volumes and locations of the LCs were compared between CT simulation images and different sequences of MR simulation images using deformable image registration. Results:The volumes of LC T2, LC 2T1, LC 5T1 and LC 10T1 were all larger than that of LC CT. A statistical significance was found between the volume of LC CT and those of LC 2T1 or LC 5T1, respectively (both P<0.05). The conformal index (CI), degree of inclusion (DI), dice similarity coefficient (DSC) and the distance between the center of mass of the targets (COM) of LC CT-LC 10T1 were better than those of LC CT-LC T2, LC CT-LC 2T1 and LC CT-LC 5T1, however, there was no statistical difference among them (all P>0.05). Conclusions:It is feasible to delineate the LC based on prone delayed-enhancement MR simulation images in patients with low CVS after BCS. Meanwhile, the LCs derived from prone delayed-enhancement T 1WI of 10-minute are the most similar with those derived from prone CT simulation scans using titanium clips, regardless of the volumes and locations of LCs.

Objective To investigate the clinical value of high-resolution magnetic resonance imaging(HR-MRI)combined with nomogram model in predicting the risk factors of positive circumferential resection margin(CMR)in rectal cancer surgery.Methods A retrospective analysis was conducted on preoperative data from 107 rectal cancer patients who underwent surgery and were confirmed by pathology.SPSS 2 5.0 software was used for univariate statistical analysis of potential risk factors for positive CRM,and after independent risk factors were selected,multivariate logistic regression analysis was performed to classify the risk factor categories.R software(4.2.0 version)was used to establish the nomogram model,and a curve was drawn to evaluate the model.The receiver operating characteristic(ROC)curve was used to show specificity and sensitivity,the area under the curve(AUC)was used to evaluate discriminative ability,the calibration curve was used to evaluate calibration,the decision curve analysis(DCA)was used to evaluate clinical benefit,and the model was internally validated using the Bootstrap method.Results Tumor located in the lower rectum[P=0.01,odds ratio(OR)=8.71],maximum diameter of tumor perpendicular to the intestinal tube(≥18.86 mm±5.32 mm)(P=0.01,OR=1.24),extramural vascular invasion(EMVI)(P＜0.01,OR=0.03),and mesorectal lymph node metastasis(P=0.01,OR=0.15)were independent risk factors for positive CRM in rectal cancer.The nomogram model established based on these factors had a training set AUC of 0.921(sensitivity 0.83,specificity 0.93),a validation set AUC of 0.912(sensitivity 0.87,specificity 0.82),a Bootstrap internal validation corrected AUC of 0.92,and a consistency index(C-index)of 0.92,indicating good discriminative ability,calibration,and clinical benefit value.Conclusion HR-MRI combined with nomogram model predicted that tumor located in the lower rectum,maximum diameter of tumor perpendicular to the intestinal tube ≥(18.86±5.32)mm,EMVI,and mesorectal lymph node metastasis are closely related to positive CRM in rectal cancer.